Kriging‐based robotic exploration for soil moisture mapping using a cosmic‐ray sensor

Soil moisture monitoring is a fundamental process to enhance agricultural outcomes and to protect the environment. The traditional methods for measuring moisture content in the soil are laborious and expensive, and therefore there is a growing interest in developing sensors and technologies which can reduce the effort and costs. In this work, we propose to use an autonomous mobile robot equipped with a state‐of‐the‐art noncontact soil moisture sensor building moisture maps on the fly and automatically selecting the most optimal sampling locations. We introduce an autonomous exploration strategy driven by the quality of the soil moisture model indicating areas of the field where the information is less precise. The sensor model follows the Poisson distribution and we demonstrate how to integrate such measurements into the kriging framework. We also investigate a range of different exploration strategies and assess their usefulness through a set of evaluation experiments based on real soil moisture data collected from two different fields. We demonstrate the benefits of using the adaptive measurement interval and adaptive sampling strategies for building better quality soil moisture models. The presented method is general and can be applied to other scenarios where the measured phenomena directly affect the acquisition time and need to be spatially mapped.     

Long-term experiments with an adaptive spherical view representation for navigation in changing environments

Real-world environments such as houses and offices change over time, meaning that a mobile robot’s map will become out of date. In this work, we introduce a method to update the reference views in a hybrid metric-topological map so that a mobile robot can continue to localize itself in a changing environment. The updating mechanism, based on the multi-store model of human memory, incorporates a spherical metric representation of the observed visual features for each node in the map, which enables the robot to estimate its heading and navigate using multi-view geometry, as well as representing the local 3D geometry of the environment. A series of experiments demonstrate the persistence performance of the proposed system in real changing environments, including analysis of the long-term stability.     

Declarative approach to cyclic steady state space refinement: periodic process scheduling

Problems of cyclic scheduling are usually observed in flexible manufacturing systems which produce multitype parts where the automated guided vehicle system plays the role of a material handling system, as well as in various other multimodal transportation systems where goods and/or passenger itinerary planning plays a pivotal role. The schedulability analysis of the processes executed in the so-called systems of concurrent cyclic processes (SCCPs) can be executed within a declarative modeling framework. Consequently, the considered SCCP scheduling problem can be seen as a constraint satisfaction problem. Such a representation provides a unified way for evaluating the performance of local cyclic processes as well as of multimodal processes supported by them. Here, the crucial issue is that of a control procedure (e.g., a set of dispatching rules), which would guarantee the cyclic behavior of the SCCP. In this context, we discuss the sufficient conditions guaranteeing the schedulability of both local and multimodal cyclic processes, and we propose a recursive approach in designing them.     

Generation and selected reactions of chlorinated thiocarbonyl S-imides*

N-Aryl-1,1,1-trichloromethanesulfenamides ArNH-SCCl₃ easily undergo dehydrochlorination upon treatment with potassium hydroxide in ethanolic solution. The intermediate thiocarbonyl S-imides formed thereby behave differently depending on the type of the N-aryl group. The sterically crowded N-(2,6-dimethylphenyl)- and -N-(2,4,6-trimethylphenyl)-1,1,1-trichloromethanesulfenamides yield the corresponding sulfur N,N′-diaryldiimides via a multi-step reaction, whereas the less crowded 2-methylphenyl and 4-methylphenyl derivatives undergo a regioselective ‘head-to-head’ dimerization leading to 5,5,6,6-tetrachloro-1,4,2,3-dithiadiazinanes in high yields. An identical reaction course is observed in the case of the 4-methoxy- and 4-bromoaniline derivatives. A diradical mechanism is postulated to explain the ‘head-to-head’ dimerization pathway.     

Influence of ligno-cellulosic particles on tribological properties of boards

There are two main possibilities to substitute conventional wood material in the panel production: the use of wood of fast-growing trees plantations and/or the use of alternative ligno-cellulosic raw materials. Especially particleboards produced from the ‘‘energetic’’ willow present the same or better mechanical parameters compared to particleboards conventionally produced mainly from soft woods. Increasing bio-fuel production, mostly from rape, will cause an escalation of the rape cultivation area and, as a result, will augment the amount of waste (rape straw) to be utilized. The aim of this study was to verify the friction coefficient of the new board types in tribological contact with tools surfaces. The investigations were performed in situ. The results of the friction coefficient related to the tools surfaces as well as lingo-cellulose materials are presented.